If you use Imperial Dry Lube (powdered graphite) you won't need to tumble after using the mandrel.
Mandrel as last step?
- Thread starter Cornholeo
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Alex Wheeler
Well-Known Member
I do not use mandrels. The idea they push variations to the outside is not true. You would have to expand enough for the brass to yield. And even then the thicker parts will spring back more, to the inside. The other issue with them is neck tension is more important that most realise. Some combos like light and some like heavy. The amount of neck tension is as important as seating depth or powder charge. Its the number one mis understood thing in tuning. You dont just pick a random neck tension like .002 and run with it. Another issue is your forced to use a lube with a mandrel, another thing I dont want to do.
I was wondering if someone would mention this.
Before and after with a CMM will show the imperfections don't magically move to the OD leaving a perfectly round neck ID.
I kind of wonder about that? I feel that it still comeback to cutting your necks to start with. It may not be the perfect thing, but it should help. I noted a long time that my groups tighten up some after cutting my necks for thickness. Some of the those neck I cut back then, were a long ways out to start with. That may not get it totally correct, but it should help. So I am will continue to cut my necks. I also started to get my own reamers to chamber my barrels now. Those reamer can be sent back and recut if needed.
I haven't taken time to check on the necks to see what changing on the necks I.D. in or out a few days down the road. I am aware of it, but that's as far as I have gone, presently.
I haven't taken time to check on the necks to see what changing on the necks I.D. in or out a few days down the road. I am aware of it, but that's as far as I have gone, presently.
Wouldn't it be better to take fired brass with it's body and neck OD conformed to the chamber under pressure, then single point turn the neck ID with fixturing off the body. It seems to me that would leave you a piece of brass with the neck ID concentric to the body OD and uniform in thickness.
BillLarson
Well-Known Member
Thats the way to do it..... basicly.....
tite neck chambers lead to a little more effort......
neck turn,fireform then anneal.
MagnumManiac
Well-Known Member
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Finding this thread interesting.
Neck tension is only held by the amount of springback, as Mikecr correctly said early in this thread. How we as loaders change this is by annealing necks. Some brass has smaller or larger quantities of zinc, this changes spring back amount.
After shooting F-class for a long time, a few things were learned a long the journey.
Number one is brass BRAND.
Number 2 is annealing consistently.
Number 3 is working the neck as little as possible.
Number 4 is using a dry neck lube.
Number 5 is bullet seating with a sleeve style die.
Number 6 is SEATING DEPTH and NECK SIZING DEPTH MATCHING BULLET SHANK DEPTH.
I have tested and found that HOW you set your neck interference is ALWAYS best when the neck is expanded to desired diameter. I threw out, or gave away, all of my bushing dies years ago and switched to honed neck dies and TAPERED sizing buttons, or mandrels.
My best F-class rifles run .0005" to .0015" neck tension (interference fit) on a 30 cal and, on a 26 cal this number ran .001" to .002".
Nothing higher ever worked.
Another fact regarding neck tension is that it alone rarely ever changes start pressure significantly to alter an outcome.
The only way to change start pressure any significant way is to use a crimp…exactly what the ammo factories do.
Have tested this over the Pressure Trace II on many occasions… not advocating that you crimp, just stating a fact.
Cheers.
Neck tension is only held by the amount of springback, as Mikecr correctly said early in this thread. How we as loaders change this is by annealing necks. Some brass has smaller or larger quantities of zinc, this changes spring back amount.
After shooting F-class for a long time, a few things were learned a long the journey.
Number one is brass BRAND.
Number 2 is annealing consistently.
Number 3 is working the neck as little as possible.
Number 4 is using a dry neck lube.
Number 5 is bullet seating with a sleeve style die.
Number 6 is SEATING DEPTH and NECK SIZING DEPTH MATCHING BULLET SHANK DEPTH.
I have tested and found that HOW you set your neck interference is ALWAYS best when the neck is expanded to desired diameter. I threw out, or gave away, all of my bushing dies years ago and switched to honed neck dies and TAPERED sizing buttons, or mandrels.
My best F-class rifles run .0005" to .0015" neck tension (interference fit) on a 30 cal and, on a 26 cal this number ran .001" to .002".
Nothing higher ever worked.
Another fact regarding neck tension is that it alone rarely ever changes start pressure significantly to alter an outcome.
The only way to change start pressure any significant way is to use a crimp…exactly what the ammo factories do.
Have tested this over the Pressure Trace II on many occasions… not advocating that you crimp, just stating a fact.
Cheers.
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Mikecr
Well-Known Member
Turning ID is not better than turning OD.
Never turn ID. Only OD. It's been my understanding that turning the brass new is better that after the fact.
Mikecr
Well-Known Member
You're right Mike.
Two reasons it's best to turn (not ream), on new brass:
1. You can easily get best mandrel fit with new brass
2. Touching new shoulders with a turner mitigates early/problem donut formation
There is no way to get back to these ideal conditions with fired brass.
Two reasons it's best to turn (not ream), on new brass:
1. You can easily get best mandrel fit with new brass
2. Touching new shoulders with a turner mitigates early/problem donut formation
There is no way to get back to these ideal conditions with fired brass.
Depending on your purpose. If getting a mid size game at 200 or less yards is, your standard Redding will be good enough for me. Long range hunting and competition shooting…mandrel as a second step is my preferred method. The problem is, brass neck thickness varies making your inside neck diameter inconsistent after resizing. Sorting brass according to thickness, using appropriate sizer and running through mandrel of desired diameter helps. If you want to go further neck-turning may be something to consider. Hope that helps. Good luck.
M1A1ABRAMS
Well-Known Member
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Alex Wheeler
Well-Known Member
Turning high quality brass does very little to help group size. And thats just using a bushing too. Many of my long range Benchrest customers have went to no turns. Most just use bushings, but some also mandrel. You can have success either way. I can say, about 75 percent of the long range records on the books are neck turned, non annealed, bushing only. And lots of neck tension. I simply do not know the other 25%. If you take away anything from this thread, I hope it is to test neck tension at distance. It can make or break a tune. If I had to pick a neck tension without testing it would have to be .005. Thats based on a lot of 1k groups testing this stuff. But Id hate to have to pick without testing. Any time I think I find a rule, I find a combo that wants something different
Varmint Hunter
Well-Known Member
Alex - thank you for your input.
I'm curious to know if those that neck turned did so to achieve more consistent neck wall thickness, or were they turning to accommodate tight neck chambers, or were they creating a specific amount of bullet release?
